Initial sprout growth of potato seed minitubers under salt stress

Potato (Solanum tuberosum L.) is a major crop worldwide and the tuber yield of currently used cultivars is strongly reduced at high soil salt levels. The effects of salt stress on early sprout growth of potato plants were investigated using the cultivar Agata. Potato seed minitubers were planted in 0.4 L pots filled with commercial substrate (Bioplant (R)), and maintained under greenhouse conditions. A completely randomized design with five treatments and five replications was used. Three days after sprouting, potato plants were exposed to five salinity levels [0 (control), 25, 50, 75 and 100 mmol L-1 of NaCl] for 28 days. Results showed that the exposure of plants to 100 mmol L-1 NaCl reduced the shoot height (72%), shoot dry matter (76%) and root dry matter (75%) of potato plants compared to the NaCl-free control. The length of longest roots was not affected by salinity levels, indicating that inhibition of shoot growth is more severe that of the root. The exposure to high salt concentrations severely restricted the early sprout growth of potato plants. Results of this study stated that salt-stress is a constraint on potato production, and the use of cultivars tolerant to salt stress can be a strategy to achieve high levels of potato tuber yield under salinity conditions.